Commentary on "Trends in Scores on Tests of Cognitive Ability in the Elderly U.S. Population, 1993-2000" : Beyond inconsistent results: finding the truth about trends in late-life cognitive funtioning

Two years ago, Freedman, Aykan, and Martin (2001) reported that the percentage of older Americans with severe cognitive impairment had declined significantly from 6.1% in 1993 to 3.6% in 1998. These apparent improvements were not explained by changes in demographic and socioeconomic composition or the prevalence of stroke, vision, or hearing impairments. We concluded cautiously that older persons appeared to have better cognitive functioning at the end of the decade. In a companion piece (Freedman, Aykan, and Martin, 2002), we showed that these results were robust to a variety of assumptions about missing data, loss to follow-up, and the institutional population, and called for replication with future waves of the Health and Retirement Study (HRS).